Northern Territory in July 2011: Typical Dry Season Conditions

After more than a year of extreme weather in the Northern Territory, July 2011 was refreshingly average. July was the first month since October 2010 that Darwin Airport measured above average mean maximum temperatures. Minimum temperatures were near average across most of the Territory, following record cool minimums in May nad June.

Rainfall was also near average for the dry season. Only the far south-western Alice Springs and the eastern Arnhem districts measured any rain for the month, with one station, North East Island, breaking a monthly rainfall record with 8.8 mm.

Coolest August-July period on record

The 12 month period from August 2010 to July 2011 is the coolest August to July period for maximum temperatures at 1.62 °C below the average. This is also the second coolest 12 month period on record (comparing any 12 month period). The record was set from December 1973 to November 1974 where the mean maximum temperature was 1.64 °C below the average.

Heavy Rains near Yulara

On July 13th, a passing trough over the Alice Springs District dumped 21.6 mm of rainfall at Yulara. This 24 hour rainfall total exceeded the monthly average at Yulara by 0.4 mm. The rainfall on the 13th combined with the rain from the previous week, bringing the rainfall total to 37.4 mm. Light showers continued on the 14th, 15th and 17th to bring the monthly total to 41.4 mm, nearly double the July average.

Rainfall

July is typically very dry across the NT, and July 2011 was no exception with area averaged rainfall across the Territory being just 5.0 mm. Apart from the far south
where stations like Yulara recorded nearly double the average July rainfall,
stations outside the Alice and east Arnhem Districts received close to average rainfall
for the month.

The wettest overall was Yulara Aero with 41.4 mm, followed by Curtin Springs with 34.0 mm, and then Tobermorey with 30.2 mm. The only rainfall record set this month was at North East Island where, with a monthly total of 8.8 mm, they measured their highest total July rainfall on record. The wettest single day was at Tobermorey with 29.0 mm on the 15th, followed by Walungurru with 21.8 mm on the 13th, and then Yulara Aero with 21.6 mm also on the 13th.

Temperature

Mean temperatures across the Territory were near average for the month. Places like Gove Airport and Katherine Aviation Museum measured exactly average for the month. Darwin Airport finished the month with a mean temperature of 25.2 °C, which is 0.3 °C above average. The mean temperature at Alice Springs was 12.0 °C which, while one of the coldest locations in the NT, is 0.1 °C above average for July.

The warmest on average was Cape Don and Jabiru Airport which both had 26.2 °C, followed by Black Point with 25.5 °C, and then Pirlangimpi and Warruwi both with 25.3 °C. The coolest on average was Arltunga with 11.0 °C, followed by Curtin Springs with 11.7 °C, and then Alice Springs Airport with 12.0 °C.

Maximum temperature

The hottest days in the Territory were all at Noonamah where the mercury rose to 35.5 °C on the 17th, 35.0 °C on the 16th, and 34.7 °C on the 18th. It is no surprise then that the warmest days on average were at Noonamah with 33.0 °C, this was followed by Jabiru Airport with 32.4 °C, and then Middle Point with 32.2 °C.

The coolest days on average were at Kulgera with 19.3 °C, followed by Yulara Aero with 20.0 °C, and then Arltunga with 20.1 °C. The coldest day was at Kulgera with 10.2 °C on the 13th, followed by Alice Springs Airport with 10.5 °C on the 14th, and then Curtin Springs with 10.8 °C on the 13th.

McCluer Island was the only location in the Territory to break a temperature record this month where, on the 31st, they measured their highest July temperature on record with 30.2 °C. Their previous record was 29.9 °C measured on 28 July 2009.

Minimum temperature

There were 23 nights when the minimum temperature at Darwin Airport dropped below 20 °C. The average minimum temperature at Darwin Airport this month was 19.3 °C which is the average for July. Alice Springs measured 6 nights below freezing, which is also average for July. The average minimum temperature in Alice Springs this month was 3.5 °C which is 0.5 °C below the July average.

The coldest nights were at Arltunga with -6.1 °C on the 25th, -6.0 °C on the 24th, -3.2 °C on the 21st and 23rd. Therefore, Arltunga was the coldest place in the NT where the monthly average minimum temperature was 2.0 °C. The next coldest places were Alice Springs Airport and Curtin Springs with 3.5 °C, followed by Territory Grape Farm with 4.9 °C.

The warmest nights on average were at McCluer Island with 23.0 °C followed by Cape Don with 22.9 °C and then North East Island with 21.9 °C. The warmest night was at Cape Don with 24.7 °C on the 12th.

Wind

The strongest wind gust was at Central Arnhem Plateau with 63 km/h on the 8th, followed by McCluer Island and Point Fawcett both with 59 km/h on the 8th, followed by Darwin Airport with 57 km/h on the 8th, and Bradshaw with 57 km/h on the 29th.

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Northern Territory using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at
8 am on Tuesday 2 August 2011.
Some checks have been made on the data, but it is possible that results will change
as new information becomes available.

Averages are long-term means based on observations from
the years 1800 to 2009.
They are not shown for sites with less than 10 years of record in that time, as they cannot then be calculated reliably.
The median
is sometimes more representative than the
mean
of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
decile ranking
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a
percentage of the long-term mean.